TITLE: GCN CIRCULAR NUMBER: 43400 SUBJECT: GRB 260114A: Fermi GBM observation DATE: 26/01/14 16:32:46 GMT FROM: Elisabetta Bissaldi at Politecnico and INFN Bari E. Bissaldi (Politecnico and INFN Bari) reports on behalf of the Fermi GBM Team: "At 11:40:26.31 UT on 14 January 2026, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 260114A (trigger 790083631 / 260114486), which was also detected by the Swift/BAT (Eyles-Ferris et al. 2026, GCN 43396). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight at the GBM trigger time is 70 degrees. The GBM light curve consists of a bright emission episode with a duration (T90) of about 320 ms (50-300 keV). The time-averaged spectrum from T0-0.064 s to T0+0.384 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.07 +/- 0.06 and the cutoff energy, parameterized as Epeak, is 583 +/- 25 keV. The event fluence (10-1000 keV) in this time interval is (4.87 +/- 0.12)E-06 erg/cm^2. The 64-ms peak photon flux measured starting from T0+0.064 s in the 10-1000 keV band is 35.9 +/- 1.4 ph/s/cm^2. A Band function fits the spectrum equally well with Epeak = 575 +/- 29 keV, alpha = -0.06 +/- 0.06, and beta = -3.5 +/- 0.6. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog: https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html For Fermi GBM data and info, please visit the official Fermi GBM Support Page: https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"